Mud density measuring device



June 3, 1952 .1. R. PETTIGROVE MUD DENSITY MEASURING DEVICE 3 Sheets-Sheet l Filed Sept. 5, 1946 mmm IN V EN TOR.

v l l2 JA R PETTIGROVE ATTORNEYS 3 Sheets-Sheet 2 Filed Sept. 3, 1946 INVENTOR. J.R. PETTIGROVE ATTORNEYS Z June 3, 1952 J. R. PETTlGRovE MUD DENSITY MEASURING DEVICE 3 sheets-snee*u 5 Filed Sept. 3, 1946 NVENTOR. J. R. PETTIGROVE )am f ATTORN EYS Patented June 3, 1952 MUD DENSITY MEASURING DEVICE John R. Pettigrove, Beaumont, Tex., assignor to Phillips Petroleum Company, a corporation of Delaware Y Application September 3, 1946, Serial No. 694,563

This invention relates to means for determining the density of a liquid. In one specific aspect'it relates to means for determining and recording the density of drilling mud. In another specic aspect it relates to the construction. of an apparatus for weighing drilling mud, and do so automatical1y-without interruption due to accumulation of caked mud on the apparatus, and without error due to the inertia of the mud as it passes through the apparatus.

In the prior art diil'iculty has been experienced inv devices for determining and recording the density of drillingr mud due to accumulation of clay or other solid matter deposited on certain portions of the apparatus by the drilling mud. For example, the accumulation of mud on the displacement member results in changes in its weight and volume, which while sometimes somewhat compensating, in most cases results in an error in weighing the mud. Accumulation of a layer of mud on .the Wall of the chamber inwhich the displacement member hangs often results in friction with the displacement member and error. The mud valves, especially the outlet valve on thebalance tank, or operating bucket, tend to be plugged by deposits of mud, especially when the ilow of mud is stopped for any reason. I havefound that the iiow of mud should never be stopped, even in a pipe, because Whilea small ow of the mud will prevent the deposit of clay, even a momentary stopping of ilow will cause a rapid deposit of clay from the mud. Because of these enumerated difliculties of the priorart I do not know of any mud weighing device on the market, with the exception of the present invention, which will operate over long periods of time with accuracy and without periodic cleaning or scrubbing out by hand, even though many of them are provided with water sprays which operate at certain times in the cycle in a vain effort to keep the device from accumulating clay. Another difficulty in the prior art devices is that the single chamber ones do not give a steady reading due to splashing of entering mud and in the double chamber devices theV drilling mud in filling the chamber containing the displacement member tends by inertia to buoy up the displacement member so that it rides higher than it should, and because of the high viscosity of the mud in many instances the displacement member can not regain its proper level in time to give a record- One object of the present invention is to provide a mud weighing device which avoids all the above enumerated disadvantages of the prior art.

Another object is to provide a suitable. relatively cheap and simple, density recorder for liquids.

8 Claims. (Cl. '7S-33) A further object is to provide a mud weighing dev1ce for drilling mud which is automatically self-cleaning.

A nother object is to provide a mud weighing device in which the flow of mud is never completely arrested, even in the inlet pipe, or at the outlet valve of the operating bucket.

Another object is to provide means whereby the drilling mud entering the chamber containing the displacement member does not sweep the displacement member toV one side of the chamber and does not buoy up the displacement member at the critical time when measurements are beingmade.

Numerous other objects and advantages Will be apparent to those skilled in the art upon reading the accompanying specification, claims and drawings.

In the drawings Figure 1 is an elevational cross sectional view `taken along the line I-I of Figure 3, looking 1n the direction indicated, showing an embodiment of the present invention.

Figure 2 is an enlarged view of the lower part ot the balance tank, or operating bucket, of Figure 1 showing the outlet valve in discharge position.

Figure 3 is a plan sectional view of the embodiment of the invention shown in Figure 1 taken along the line 3 3 looking in the direction indicated.

I n Figure 1 is shown an assembled mud Weighing device embodying the present invention and generally designated as 4.

Mud weighing device 4 comprises a mud tank 5 supported, if desired, on a number of legs 6 and provided, if desired, with handles 'I. Tank 5 has a bottom 8 to which is connected a discharge pipe or outletl 9. A hose or pipe may be connected to 9` carrying the mud off and discharging the same into a mud pit (not shown) or other place where it will not be in the Way. So far as the operation of the mud weighing device is concerned, however, bottom 8 and outlet 9 could be eliminated.

Tank 5 is divided into ve compartments numbered II, I2, I3, I4 and I5 by means of partitions I6, I1, I8, funnel I 9 and the common bottom 2| of chambers II, I2 and I3. Bottom 2| is provided with a hole 20 connecting chambers I2 and I5. Partition I'Iis provided with a window or opening 22 connecting chambers II and I3 and part of the partition of I'IY directly above Window is bent so that it projects into chamber II at 23 as shown. -Chambers II and I3 are also connected bythe space under the lower end of, partition I'I. f

A reinforcing frame 24 may be provided at the top of tank 5 and bridge means 25 is provided extending across tank 5 to support the recording instrument generally designated as 21. Obviously a number of alternative constructions suggest themselves, but for vpurr'iosesv of illus.'-

tration'the following construction is shown because it is preferred:

To bridge 26 is attached a plate 28 and ate-V being the preferred construction.

Instrument 21 is any one of the usual recording instruments containing a clock driving a sheet of paper on which the record is made (clock and Paper Ynot S110WI @here .re..f, rding.4 arm l(not shown). for 'makina merke on the, naper; is actuated `by the turning of pin 34 mountedlinflilacket 3.6,. Pili 34. is rigidly mounted inl lever arm 31, .levier erm. 31 eirots. eroundnin Sigandtracket as. `Slilsienel@et fremilleoiherend.eilever arm 3:1 iS e'disillaeemeei member 3.8, which ,hangs the chamber '3i Displacement membereais preferal? vmede from, east, eemmereiallybronze, and pf. ieliebly.. i mee, the, somewhat. streamline ne. Shown. and out. of., one ormore. hollow '.S'- Preferably theioiiter. euraee of. as; is @Mather Smoothie, onderw make the, deposit'ofmud less and the` removalof, mild easier.Y moet iiseiiees. 3.8 Wouldbe hollow. However, Slt mariee mede soli-d. and. or wood, aluminum, magnesium. other meserialsA witheutdepertine from the present invention. Displaeementmemf ber 38 may be suspended fromA lever 3.1;"by any .seiielolemeees eilen, as a ehainJ er. wire Se, providedI with suitable fastening 4|L andl 4.2.. at 'each one:

Fastening, or piret.. 411s. alsevconneeted to yoke iawhieli. .supported .by weighing. .rod 4:4` Weighieeresi. 4.4 isfihreeded and extendsfun through Peiitien 46 11.03533 into;SpringA chamnerl- Spring chamber 41 may be cylindrical andinternally 'threaded Any upper: stepmembenia is 011,1 desi into. chambery ,and may he fsetatthe eoioitiskdesired te stop upward movement. of spring contacting member 49. Member 49.. is ihreeeledenrod 4.4 Se. that itjmay beplositioned te. sive., the. desired eernpressioni on spring. 5i.

" AISO threaded er1 rod. lgis a lower-.stop member @which limitstheeownnerd morementofzrod V34,.against.eharnleer.4;,1 eren as stops #sand 49 limit the upward rrrcir/ement. Ifdesiredstopsia and. ,521. may. beprovidedwith setserews or rock nuts toLpreventmisadjustment.

Mountedoneleeveli, iria 'position behind and in. front oirpe 3|. are two. pivotsts, and the tweareis. 5:4v of e. biiureated balance lever.. 5.6 arepiveied onsaidnivots, If necessary. te .adjust thetalerieeefthe .elenee erin, amovableweignt 51 may be eroi/dedsecured.ina..nredetermined,V

adjustable.. position by. any. suitable .securing meanasuehes Setserew;

usperidediremiheright hand end .ofbaianee leren, 54 is e. balance tank. or `operating..bncizet 5.9.'. Viiiile` othergmeene may be employed; 'I- f oreferto .reinforce the. upper edge of. bucket 5.9 withriis 6i .anderer/ide piyeisz oneaenside ei-ihebeehei ,53 Arras 54 are similarly nreyided with, pivots and. pivote `6.2 .and @are pli-feierebleeilleeied-by, Sirena er reins, 64, eassinein. thespeee between formel liano ,tense .Witheet contacting either.

The heitere. eibuekeif-eie pronged-with en outlet valve gener ll'yx desgnated asu lwhich iiieiweieel describes iiinieireieieii..wenneerence to Figure 2. However, valve 66 has an operating foot 61 which is designed to contact bars 6.6 when the buckety'tv'isflowered Bars 68` arel secured in thefrm 0f a', vgrill'Y to tank 5 by means of supporting members 69.

"The common bottom 2| is provided with an outletopening 1| and this outlet opening is controlled by a valve head 12. An inlet pipe 13 is, provideclforA feedingmud to the device and said inlet pipe has a"downwardly directed opening which is controlled by valve head 14. Valve heads 12 and 14 are shown as solid rubber balls of a moderate degreeof softness, but need not necessarily be solid as toilet flush bowl valves of the usual hollow design have also rbeen found to be satisfactory. The valve, lzissupnorted and-cnnt'rolled by rod 16; and valve 14. suppbrtedand controlledv by sleeve 1 1.. Sleeve. 11x is4 externally threaded at 18:andinternally.threadedatl 1.6. A nut.'8,|. is threaded. on thread. 18, andfthread 19 is. threaded on threads 8,2..of..rod.1 6 Thelproner spacing o'ffthe valves cbviouslymay be achieved by. adjusting these various threads and nutsin additionrlock nuts'such. as.83fmay` be provided and further adjustmento'fvalve. 12 may be ob.- tained by threads 84and 4niit 5, Varioiischanges may be made without departing fro'mtheinven.- tion' as for example in some instances sleeyelfl need Vnot have' internal threads" 19, in. which case nut 8.3. and' grav'ityiare relied on to -space l'ower valve 12. Nut 8|."rides on thef'top of. leyen and sleeve 1.1. containing rod. 1.6...passes through opening86in thelever5l6 As shown in Fig-ure 1,'valve 1.2. isclosedeand itis obvious thatwhen bucket. 59,goes downand theleft side oilever 55 goesupthat valvej will close pipe 13'.while valve 1.2.will openbpening 1|. It -shouldalso benoted, thatthrcads 18 extend down into pipe 1,3and.rec'eive therein a nu't. 81. `Nut 81, may ibe positioned topick up weighed. sleeve Samy 'means ofthe' overnangiri'g portion '89 at the proper moment that valve 1.2lis pulledofiiits' Seat'an'd has therebylost-"a good portion ofthe staticv head formerly holding itin place.

'iA`spray pipe 9| is providedwith outwardly directed. orifices to spray the inner Walls of chamber I3, and a spray pipe 92..ispovidedwith two' oppositely spaced orifices 9.3, 'which orices 93 are'directedto cause their spray'to strikethe displacement member 38 .ata point adjacenttlie a'pex atits upper cone adjacent fasteningmean's 4|. 'Sprays 93|i'a`nd 92 are, not shut'foffJdniing thenor'maloperation of the device.

` Figurezshows the lower portion of.bucket,59 and Vvalve 66inmre detail. While 'thel bucket 5'9' could be nade integral, .I prefer'to'inserta thicker andlmore accurate valve seat '94l which is" not! subject 'to Warpngf under strain. Seat V9d is provided'with an outlet 'orifice gaanda yit androdlz, Red llfmarbe nroxidedwith operating foetiiiee este be ,eureio eentaet with at least one of rods 68. Rod |02 also ha ,a cellar, l Secured .thereto ley. stepA means. such as aeeteerew '0i sel ther-Coller, |93 men-be positioned to open valve 66 in the proper.'v

tion of bucket 59. In order to close valve 66 and also in order to not lose operating rodl I02, rod |02 is provided with an upper stop 'member IUI;` which'is preferably made in the form of a semicircular spring arm, as shownyin'order to absorb some of the shock -to bucket 59 when it picks up rod |02 and foot 61. Stop member |08 may be positioned in'any suitable manner at the top of rod |02, such as by threads |01, upper and lower nuts |08 and lock nuts |08.

Figure 3 shows a plan sectional View of the structure shown in Figure l taken along the line 3 3 of Figure l, looking downward. As such, many of the parts of the assembly 4 have the same numbers as in Figure 1 and therefore will only be discussed as may be necessary.

The drilling mud may come from any portion of the system (not shown), which consists of a mud pit and conduits leading to and from the well, but preferably the mud is'taken from the mud returning to the surface in the well by means of a branch pipe III which is connected to the mud return pipe (not shown). Obviously all of the mud coming out of the Well can not pass through the mud recording device inl most in- I throttled to control the flow of mud, butv which l.

valve is never shut off except at those rare intervals at which it is desired to completely clean the equipment, or to disconnect the same. v Pipe III is connected to pipe 13 by means of a T ||3, and T II 3 is connected with clear 4water pipe II4, but'except for complete clean outs (which occur only at very long intervals) fresh water cannot enter T I I3 because valve I I5 in pipe I I4 is closed. Upstream of valve ||5 in pipe II4 are Ts IIB and II1. These Ts are connected to pipes 9| and 92 by valves ||8 and ||8 respectively.

Valves IIB and ||9 control the force of their respective sprays, such as 93, and generally remain set in one position as they run through all stages of the cycle of the operation. At the complete clean out period (which occurs at long intervals of time) they may be open a bit wider in order to increase the force of the spray if desired. l

Because it is very important that the drilling mud does not stop iiowing at any point in the system an orifice (not shown) is provided in pipe 13 constantly discharging mud I2I into chamber I2 at a varying rate throughout all cycles of operation. The size of this discharge |2I is regulated by a rotating valve member |22 which is provided with an adjusting handle |23 and suitable means for positioning it, such as slot |24 and set screw |26. Visible through the top of pipe 13 is sleeve 11 and rod 18 which are .described with reference to Figure l. The end of pipe 13 may be terminated by a bull plug, or other closure |21. An advantage of a removable closure |21 is that the device may be connected up by attaching mud pipe III in place of cap |21 and movingv cap |21 over to attach to a nipple inserted in T ||3 Vin place of pipe III, thus changing the device from a right handed into a left handed device to suit the particular location, if needed. y

Operation III to a source'of drilling mud and by pipe' I I'Il to a source of relatively clear water. Therela'- 6. tively clear water can actually be fairly dirty, but still it is relatively clear compared to the mud.

The proper positions for valves 12, 14 and 66 may be adjusted before taking the device into the field by means of nuts 8|, 83, 85, |04, |08, |09 and related parts. Stop members 48, 49 and 52 also may be adjusted before taking the instrument into the field.

Valve II5 is closed and valves |I2, ||8 and IIS are opened to the desired degree.

As the mud flows through line I into pipe 13 the discharge at I2| is regulated by moving handle |23 and setting set screw |26 so that there may be a constant flow of fair volume at all times in 13. Assume the device has taken the position shown in Figure 1 which it will take when empty. The mud pours out of pipe13 into chamber VI I and is deiected from Window 22 by means of ledge 23. As opening 1| is closed by valve 12 chambers and I3 proceed to ll. At the same time spray, 93 and the spray from 9| continue to Wash down the displacement member 38 and the walls of the displacement member chamber I3.

The vmanner of filling chamber I3 with mud is very important because a vquick upper travel of mud inV chamber I3 will result in an overtravel upwardlyv of the displacement member 38 while if the mud vis allowed to travel side ways into chamberl I3 it will force displacement member 38 over against partition I8 resulting in friction and' thenthe displacement member will not raise high enough.

Since it is not possible to reduce the' filling velocity because this would unduly lengthen the cycle of operation and would tend to cause deposits of clay from the drilling mud in pipes 13 and III, it is necessary to counteract the causes for overtravel and turbulence.

At rst the mud flowing from 13 into chamber II passes under the lower edge of partition |1, but as only the lower conical type of member 38 projects into that portion of the device there is relatively small displacement side ways of member 38. The mud then raises in chamber I 3 until the level of the mud reaches the bottom of win- By this time the member 38 has been dow 22. buried deep enough to resist any side sway, but has been buoyed up a little. However, some time remains'for the displacement member 38 to sink by gravity in the thick mudV to overcome the buoying effect. As the mud rushes side ways from chamber into chamber I3 through window 22 there is substantially little mud passing below partition I1 so there is no buoying effect on mem ber 38. The lower edge of window 22 is high enough relative to member 38 so that member 38 has-a larger portion anchored in substantially quiet mud in chamber I3 and so the `mud coming in through window 22 can neither buoy up or displace side ways the member 38. The top of win- `dow 22 is designed to be below the top of partition I8 so that the mud owing from chamber I 6 down under edge 23 at the end of-the filling cycle enters chamber I3 very quietly so that the instrument 21 can make a steady reading. During the vtime taken by this portion of the cycle the amount of water entering through spray 93 is negligible and does not eect the reading of the instrument within the degree of accuracy required. The same is true of water from spray 9| which along with the spray from 93 tends to stay on top of the mud but which also tends toV stay over to the side of chamber I3.- I

At this point in the cycle asthe drilling mud ows through funnel I 4 into bucket 58 the recordextending down below the major portion 0f said displacement means a sufficient distance to insure said displacement member remaining away from the wall of said iirst tank as mud from said valve means sweeps under said partition, and said partition extending up above the major portion but below the upper conically-shaped end of said displacement means to insure said displacement member remaining away from the wall of said rst tank while mud from said valve means sweeps across the top of said partition and said displacement member takes its proper vertical position.

3. A device according to claim 2 wherein said second tank contains a liquid dumping device adapted to open and close in a discharge outlet in the bottom of said second tank which comprises a valve stem, a closure unit slidably mounted on said stem and adapted to seat in said outlet and close the same, said closure unit having an opening therethrough of greater cross section than the valve stem, leaving suflicient clearance through which the fluid continuously ows thereby lubricating the moving parts of said dumping device, a stop on said stem adapted to engage said closure unit, and means for eiecting relative movement between said tank and said valve stem.

4. In a device for recording the density of drilling mud having a rst tank wherein a sample of said mud is accumulated, displacement means within said rst tank for measuring the density of the sample, recording means responsive to the displacement .of said displacement member for recording said density, a beam pivotally mounted above said rst tank, a -second tank suspended from said beam and positioned to catch an overow of said mud from said first tank, and valve means operatively connected to said beam to control the filling of said rst tank, the improvement comprising a drain valve for said rst tank operatively connected to said beam by a valve stem, and a weight slidably mounted on said stem, said weight resting on a stop when said drain valve is closed and adapted to be engaged by a stop on said stem when said drain valve is open to add weight to said beam to compensate for the static head formerly holding said drain valve shut.

5. A device according to claim 4 wherein said second tank contains a liquid dumping device adapted to open and close in a discharge outlet in the bottom of said second tank which comprises, in combination, a valve seat, a valve head disposed Ato close against said seat, said valve head having an opening therethrough extending from one side of said valve seat to the other, a valve operating rod extending through said opening in said valve head, stops on said rod above and below said valve head engaging the same, said rod being sufficiently smaller in diameter than the opening in said head to lpermit a fluid to flow through said valve head whereby deposits of solid material from said uid owing through said valve head and consequent sticking of said dump valve are substantially reduced.

6. An improved mud weighing device comprising, in combination, a tank having a mud inlet and a mud outlet, an elongated displacement member having generally conical ends suspended vertically into said tank for measuring the density of said mud, a vertical imperforate partition in said tank between said mud inlet and said displacement member dividing said tank into two compartments, said partition having a lower opening opposite a lower portion of said displacement member and a middle opening opposite an upper portion of said displacement member, thereby establishing communication between the two compartments, and means for closing and opening said mud outlet :for filling and Vemptying said tank.

7. A device for measuring the density of a drilling mud comprising, in combination, a lirst tank wherein a sample of mud is accumulated, displacement means within a iirst sector of said iirst tank for measuring the density of the sample, said displacement means having generally conically-shaped ends and being vertically disposed in said rst tank in such a manner that one of said conically-shaped ends is disposed above the other, a beam pivotally mounted above said rst tank, a second tank suspended from said beam and positioned to catch an overflow of said mud from said iirst tank, valve means operatively connected to said beam to control the lling of said first tank, said valveI means discharging into a second sector of said first tank adjacent to but laterally removed from said first sector, a vertically disposed imperforate partition in svaid first tank extending thereacross to divide saidrst tank `into said first and second sectors, said partition extending downwardly towards but not to the bottom of said iirst tank a distance such that its lower edge is below that portion of said displacement means having the largest cross-sectional area in a plane perpendicular to its vertical axis, and said partition extending upwardly towards but not to the top of said rst tank av distance such that its upper edge is above that portion of said displacement means having said largest cross-sectional area whereby mud iiowing below said partition from said first sector into said second sector contacts during its lateral ow only that portion of said displacement means having a small resistance thereto thereby avoiding any substantial misalignment of said displacement means from its proper vertical position.

8. A device according to claim 7 wherein said second tank contains a liquid dumping device adapted to open and close in a discharge outlet in the bottom of said second tank which comprises a valve supporting member positioned above said discharge outlet in said second tank, a valve stem extending vertically downward from said supporting member through said discharge outlet, an outlet closure member slidably mounted on said stem and adapted to seat in and close said discharge outlet, said closure member having an opening therethrough of greater cross section than that of the stem on which it slides, thereby forming an annular space through which uid can continuously ow from said second tank, and a stop at the end of said stem adapted to engage said plug when relative movement occurs between said valve stem and said tank.

JOHN R. PETTIGROVE.

REFERENCES CITED The following references are of record in the i'lle of this patent:

UNITED STATES PATENTS Number Name Date 2,252,014l Lupfer Aug. 12, 1941 2,285,586 Kerr June 9, 1942 2,360,977 Pettigrove Oct, 24, 1944 FOREIGN PATENTS Number Country l. Date 690,716 France June 24, 1930 

